Every once in awhile, it’s fun to plot up the data and see what they look like. Lately, it’s been especially fun because our data set just keeps on growing and growing! Right now, we have 425 436 455 verified entries, 190 183 unverified, and around 30 20 10 in the double-check queue. We’ve also added a few new contributors this week, which is another nice bonus. Excellent progress, everyone!
This time, I decided to plot tibia length versus metatarsal III length for a variety of animals (at right; click on it for an enlarged version). As in one of our earlier plots of tibiae versus femora, ankylosaurs are weird. Their metatarsals are just really, really stubby relative to the tibiae (and the tibiae were really stubby relative to the femora). Interestingly, the saurischians in our sample seem to consistently plot above the ornithischians; in other words, saurischian metatarsals are long relative to the tibia (for the basal saurischians in our sample, at least).
Some analyses of mammals have suggested that a long MT III relative to the tibia may indicate more cursorial tendencies than for animals with a short MT III. Does this perhaps hold in dinosaurs? Were saurischians speedy, and ankylosaurs plodding? Or is there a phylogenetic effect that swamps any functional signal (as suggested for the mammal patterns by some authors)? Lots of additional analyses are needed.
The plot also shows a few gaps in our verified data set. Stegosaurs, basal thyreophorans, and pachycephalosaurs are not represented at all in this plot, because we don’t have any measurements of both a third metatarsal and a tibia for any members of these groups. If you’re looking for a data entry project, these would be excellent groups upon which to focus our efforts.
Do you want to do your own analysis? You can! All of the data used to create the plot above are publicly available.